mongod --dbpath "..\db data" -- quotes are important!
mongo

use db_SampleChat

var sampleMessage = {}
sampleMessage.text = "Example text value."
sampleMessage.date = "13/07/2015"
sampleMessage.isRead = false
sampleMessage.userId = 1

db.message.insert(sampleMessage)
db.messages.insert(sampleMessage)
db.message.drop()

var sampleUser = {}
sampleUser.username = "smpl_username"
sampleUser.fullName = "First-name Second-name Family"
sampleUser.website = "www.SoftUni.bg"

db.users.insert(sampleUser)

C:\Program Files\MongoDB\Server\3.0\bin>mongoexport --db db_SampleChat --collection messages --out messagesBackUp.json
C:\Program Files\MongoDB\Server\3.0\bin>mongoexport --db db_SampleChat --collection users --out usersBackUp.json